1. Field of the Invention
The present invention relates to a liver function improver comprising, as an effective ingredient, dioxabicyclo[3.3.0]octane derivative, and to a food or drink containing this derivative having a liver function-improving action, a cholesterol level-reducing action, and/or a neutral fat level-reducing action.
2. Description of the Related Art
The liver is the largest substantial organ of a human body, in addition to the brain, and has various functions such as a detoxifying action, carbohydrate metabolism, protein metabolism, the formation and secretion of bile, the formation of blood coagulation factors, hormone-controlling action, and the action of storing various living body constituents such as fat, glycogen, proteins, and vitamins. These functions are acutely or chronically impeded by viruses, drugs, poisons, excessive intake of alcohol, malnutrition, liver circulatory system troubles, bile duct occlusion and the like, and as a result, there appear such diseases as viral hepatitis, drug doxic hepatitis, alcoholic hepatitis, congestive hepatitis, liver disorder due to a stagnation of hepatic juice fatty liver, interus, and finally, hepatocirrhosis.
For example, to remedy liver disorder caused by alcohol, there has been adopted not only a method of controlling an intake of meat fat and an excessive intake of alcohol, but also a medicinal thereapy using antihistamic agents, barbituric acid salts, adenosine triphosphate (ATP), pyrazole, a mixture of dihydroxy acetone and riboflavin, glucronic acid, arginine hydrochloride, and amino acid preparations such as glutathione. Nevertheless, the effects of these drugs are not satisfactory, and there is no certain remedial method other than a control of an excessive intake of alcohol. As one of the causes of liver disorder brought on by drugs and poisons, there can be mentioned the formation of a harmful oxygen free radical, and accordingly, a large quantity of glutathione is administered for theraphy of toxicoses and allergic diseases. Especially, for a protection of cells, glutathione reduces or extinguishes an active oxygen species or free radical by glutathione peroxidase, or glutathione reacts with a poison through glutathione-S-transferase and discharges the poison from cells in the form of a glutathione conjugate, to exert the intended function whereby antioxidation, detoxification and a protection from radiation damage can be achieved. Nevertheless, even if glutamine per se is administered, the half-life is short (only several minutes) and tissue glutathione is not effectively increased. Accordingly, the development of glutathione derivatives and the like is now under investigation.
Under the above circumstances, however, the development of a novel liver function improver is urgently required.